Chapter 8 - An Introduction to Metabolism

Exergonic Chemical Reaction

chemical reaction that releases energy. breaking polymers. -ΔG

Endergonic Chemical Reaction

chemical reaction that requires input of energy. building polymers. +ΔG

ΔG

change in free energy and the ability to do work

Entropy

measure of disorder

ΔG Formula

ΔG = ΔH - (T)ΔS

ΔH

change in enthalpy

ΔS

change in entropy

T

absolute temperature in K

K

C + 273 degrees

-ΔG

loss of energy and is spontaneous (exergonic)

+ΔG

gain in energy and is non-spontaneous (endergonic)

ΔG decreases

as cells move towards equilibrium

Calls are not in equilibrium

because cells are in an open system

catabolic pathway

in a cell releases free energy in a series of reactions

where does necessary energy come from?

coupling exergonic reactions (releasing energy) with endergonic reactions (needing energy)

the kind of system that organisms are

endergonic

Energy is needed for

synthesis (biomolecules), reproduction, active transport, movement, temperature regulation

ATP

an energy currency (adenosine triphosphate)

Energy is released from ATP

when the terminal phosphate bond is broken

phosphorylation

transferring a phosphate group to some other